Search Results for: 4017

The presented LED chaser with blinker circuit using IC 4017 was requested by Mr.Joe, one of the keen followers of this blog. The circuit initially was intended to be used for generating LED strobe light effects and was asked to be modified such that it could be used as an LED sequencer as well as a blinker. The change over would be implemented via a toggle switch.

The circuit diagram may be understood with the following points:

The IC 4017 is not new to us and we all know how versatile and competent this device is. Basically the IC a Johnson’s decade counter/divide by 10 IC, fundamentally used in applications where sequencing positive output signals are required or desired.

The sequencing or the orderly shifting of the outputs take place in response to a clock pulse that needs to be applied at the clock input pin #14 of the IC.

With every rising positive edge of the clock input, the IC responds and pushes its output’s positive from the existing pin out to the next pin out in the order.

Here a couple of NOT gates are used as a oscillator for providing the above clock pulses to the IC 4017. VR1 may be adjuted for determining or fixing the speed of the sequencing.

The outputs of the IC are connected to an array of LEDs in a specific order which makes the LEDs look like as if they are running or chasing during the operations.

If the circuit would be required only to produce the chasing effect, the diodes would not be required, however as per the present ask the diodes become important and allows the circuit to be used as a blinker also, depending upon the position of the switch S1.

When the switch S1 is positioned at A, the circuit behaves like a light chaser and produces the normal chasing effect over the LEDs which start illuminating in sequence from top to the bottom, repeating the operations as long as the circuit remains powered.

As soon as S1 is flicked toward B, the clock signals from the oscillator are shifted into the input of the transistor T1, which instantly stats to pulsate all the LEDs together in response to the received clocks from N1/N2 configuration.

Thus as per the requirement we have successfully modified an ordinary light chaser circuit with an additional feature through which the circuit now is also able to function as a LED flasher.

Do not forget to connect the inputs of the remaining unused gates from the IC 4049 either to the positive or the negative of the supply. The supply pins of the IC 4049 also need to be connected to the relevant supply rails of the circuit, kindly refer to the datasheet of the IC.

If all the ten outputs of the IC 4017 are required to be integrated with LED sequencing, just connect pin #15 of the IC to ground and use the left over outputs of the IC for the required sequencing of the LEDs in the order of: 3,2,4,7,10,1,5,6,9,11

The following parts will be needed for making this LED light chaser cum flasher circuit:

The IC 4017 can be considered as one of the most useful and versatile chip having numerous electronic circuit applications.

Introduction

Technically it is called the Johnsons 10 stage decade counter divider. The name suggest two things, it’s something to do with number 10 and counting/dividing.

The number 10 is connected with the number of outputs this IC has, and these outputs become high in sequence in response to every high clock pulse applied at its input clock pin out.

It means, all its 10 outputs will go through one cycle of high output sequencing from start to finish in response to 10 clocks received at its input. So in a way it is counting and also dividing the input clock by 10 and hence the name.

Understanding pinout Function of IC 4017

Let’s understand the pin outs of the IC 4017 in details and from a newcomer’s point of view: Looking at the figure we see that the device is a 16 pin DIL IC, the pin out numbers are indicated in the diagram with their corresponding assignment names.

The pinout which are marked as outputs are the pins which become logic high one after the other in a sequence in response to clock signals at pin#14 of the IC.

Therefore with the first clock pulse at pin#14 the first output pinout in the order which is the pin#3 goes high first, then it shuts off and simultaneously the next pin #2 becomes high, then this pin goes low and simultaneously the preceding pin #4 becomes high...... and so on until the last pin #11 becomes high.

After pin#11 the IC internally resets and reverts the logic high at pin #3 to repeat the cycle.

This sequencing and resetting is successfully carried out only as long as pin#15 is grounded or held at a logic low, otherwise the IC can malfunction. If it is held high, then the sequencing will not happen and the logic at pin#3 will stay locked.

Please note that the word “high” means a positive voltage that may be equal to the supply voltage of the IC, so when I say the outputs become high in a sequential manner means the outputs produce a positive voltage which shifts in a sequential manner from one output pin to the next, in a “running” DOT manner.

Now the above explained sequencing or shifting of the output logic from one one output pin to the next is able to run only when a clock signal is applied to the clock input of the IC which is pin #14.

Remember, if no clock is applied to this input pin#14, it must be assigned either to a positive supply or a negative supply, but should never be kept hanging or unconnected, as per the standard rules for all CMOS inputs.

The clock input pin #14 only responds to positive clocks or a positive signal and with each consequent positive peak signal, the output of the IC shifts or becomes high in sequence, the sequencing of the outputs are in the order of pinouts #3, 2, 4, 7, 10, 1, 5, 6, 9, 11.

Pin #13 may be considered as the opposite of pin #14 and this pin out will respond to negative peak signals, if a clock is applied to this pin, producing the same results with the outputs as discussed above.

However normally this pin out is never used for applying the clock signals, instead pin #14 is taken as the standard clock input.

However, pin #13 needs to be assigned a ground potential, that means, must be connected to the ground for enabling the IC to function.

In case pin #13 is connected to positive, the whole IC will stall and the outputs will stop sequencing and stop responding to any clock signal applied at pin #14.

Pin #15 of the IC is the reset pin input. The function of this pin is to revert the sequence back to the initial state in response to a positive potential or supply voltage, meaning the sequencing comes back to pin #3 and begins the cycle afresh, if a momentary positive supply is applied to pin #15.

If the positive supply is held connected to this pin #15, again stalls the output from sequencing and the output clamps to pin #3 making this pinout high and fixed.

Therefore to make the IC function, pin #15 should always be connected to ground.

If this pinout is intended to be used as a reset input, then it may be clamped to ground with a series resistor of 100K or any other high value, so that a positive supply now can be freely introduced to it, whenever the IC is required to be reset.

Pin #8 is the ground pin and must be connected to the negative of the supply, while pin #16 is the positive and should be terminated to the positive of the voltage supply.

Pin #12 is the carry out, and is irrelevant unless many ICs are connected in series, we will discuss it some other day. Pin #12 can be left open.

Have specific questions?? please feel free to ask them through your comments...all will be thoroughly addressed by me.

Application LED Chaser Circuit using IC 4017 and IC555

The following example GIF circuit shows how the pinouts of a IC 4017 is usually wired with an oscillator for obtaining the sequential logic high outputs. Here the outputs are connected to LEDs for indicating the sequential shift of the logics in response to each clock pulse generated by the IC 555 oscillator at pin#14 of the IC 4017.

You can see that the logic shift happens in response only to the positive clock or positive edge at pin#14 of the IC 4017. The sequence does not respond to the negative pulses or clocks

A very simple yet effective electronic toggle flip flop switch relay circuit can be built around the IC 4017 and IC 4093, we will see how this can be implemented from the following explanation.

What's a Flip Flop Circuit

A flip flop relay circuit works on a bistable circuit concept in which it has two stable stages either ON or OFF. In When used in practical applications circuits it allows a connected load to alternately toggle from an ON state to OFF state and vice versa in response to an external ON/OFF switching trigger.

In our following examples we will learn how to make a 4017 IC and 4093 IC based flip flop relay circuits which are designed to respond to alternate inputs triggers, and correspondingly operate a relay and a load alternately from an ON state to OFF state and vice versa.

By adding just a handful of other passive components the circuit can be made to toggle accurately through subsequent input triggers either manually or electronically.

A couple of very useful flip flop toggle switch circuits are explained here.
They may be operated through external triggers either manually or an electronic stage. Circuit schematics of these flip flop circuits have also been included.

Simple Electronic Toggle Switch Flip Flop Circuit Using IC 4017

A very simple and effective electronic flip flop toggle switch circuit can be built around the IC 4017. The component count here is minimum, and the result obtained is always up to the mark.

Referring to the figure we see that the IC is wired into its standard configuration, i.e. a logic high at its output shifts from one pin to the other in the influence of the applied clock at its pin # 14.

The alternate toggling at its clock input is recognized as clock pulses and is converted into the required toggling at its output pins. The whole operation may me understood with the following points:

How the Circuit Works

We know that in response to every logic high pulse at pin #14, the output pins of the IC 4017 are switched high sequentially from # 3 to # 11 in the order: 3, 4, 2, 7, 1, 5, 6, 9, 10, and 11.

However, this proceeding may be stopped at any instant and repeated by just connecting any of the above pins to the reset pin # 15.

For example (in the present case), pin # 4 of the IC is connected to pin #15, therefore, sequence will be restricted and will bounce back to its initial position (pin # 3) each time the sequence (logic High) reaches pin # 4 and the cycle repeats.

It simply means that now the sequence toggles from pin # 3 to pin # 2 in a back and forth manner constituting a typical flip flop action. The operation of this electronic toggle switch circuit may be further understood as follows:

Every time a positive trigger is applied to the base of T1, it conducts and pulls down pin # 14 of the IC to ground. This brings the IC to a standby position.

The moment the trigger is removed, T1 stops conducting, pin # 14 now instantly receives a positive pulse from R1. The IC acknowledges this as a clock signal and quickly toggles its output from its initial pin #3 to pin #2.

The next pulse produces the same result so that now the output shifts from pin #2 to pin #4, but since pin #4 is connected to reset pin #15, as explained, the situation bounces back to pin #3 (initial point).

Thus the procedure is repeated every time T1 receives a trigger either manually or through an external circuit.

Accurate CMOS Flip Flop Circuit Using IC 4093

Another simple and very accurate flip flop circuit can be made using three gates of IC 4093. Looking at the figure we see that the inputs of N1 and N2 are joined together to form logic inverters, just like NOT gates.

It means that, any logic level applied to their inputs will be inverted at their outputs. Also, these two gates are connected in series to form a latch configuration with the help of a feedback loop via R5.

N1 and N2 will instantly latch the moment it senses a positive trigger at its input. Another gate N3 has been introduced basically to break this latch alternately after every subsequent input pulse.

The functioning of the circuit may be further understood with following explanation:

How the Circuit Works

On receiving a pulse at the trigger input, N1 quickly responds, its output changes state forcing N2 to also change state.

This causes the output of N2 to go high providing a feedback (via R5) to N1’s input and both the gates latch in that position. At this position the output of N2 is locked at logic high, the preceding control circuit activates the relay and the connected load.

The high output also slowly charges C4, so that now one input of gate N3 becomes high. At this juncture, the other input of N3 is held at logic low by R7.

Now a pulse at the trigger point will make this input also go high momentarily, forcing its output to go low. This will pull the input of N1 to ground via D4, instantly breaking the latch.

This will make the output of N2 to go low, deactivating the transistor and the relay. The circuit is now back to its original state and ready for the next input trigger to repeat the entire procedure.

The article describes how to make a sequential LED light chaser circuit with an sequentially illuminating LED forming a bar graph kind of LED formation.

Introduction

The article describes a simple method of making an incremental LED bar graph by using the IC 4017, which is rather equipped with specifications not suiting the present functions. Let’s learn how we can mod the IC for the operations.

Here we study an easy method of making an array of LEDs “chase” to develop into a sequential LED bar graph.

The LEDs start from one of the 10 pin outs of the IC and go on switching one after the other until all the LEDs are lit forming an incrementing bar graph. The circuit uses the ordinary IC 4017 for implementing this interesting LED light sequence.

Circuit Description

The main component of this sequential LED driver circuit is the popular Johnson’s Decade Counter IC 4017. As we all know, the normal functioning of the IC involves sequential shifting of its outputs 1 to 11, in response to a clock signal applied at its pin #14.

The outputs become high in sequence such that the previous output becomes low immediately as the “high” position “leaps” through the assigned pi-outs.

If LEDs are connected to the outputs, the above sequence would produce an effect of an illuminated “dot” jumping from start to finish and repeating the sequence.

Circuit Schematic

Though the effect looks interesting, fails to bewitch the folks simply because the illuminations produced are very low.

This is because, only one LED or lamp glows at any instant while sequencing, not enough to make the system very eye-catching. However the sequencing factor of the IC cannot be ignored as it’s one complex function that cannot be achieved a single IC and the chip must be credited for this attribute.

So, what can we do to improve the above feature such that the engaged lights become more attractive and the sequencing feature is also exploited at the same time?

One idea would be to stop the former LEDs in the sequence from shutting down while the array is sequencing. It means now as the illuminating sequence begins, the LEDs light up one after the other to form an illuminated “bar,” until the whole array is lit up. Once the whole sequence ends, the entire “bar” is shut off and the cycle repeats all over again.

However since it won’t be possible to do any modification inside the chip, probably doing this through external amendment is the option left.

To keep the LEDs hold their illuminations even with the sequencing logic going low, we would require some kind latching arrangement with the LEDs for implementing the trick. As we all know an SCR is one device which latches up its output pin outs when its gate is triggered.

The function is available only with DC supplies though, and here the circuit being operated with a DC, becomes perfectly suitable for the above application.

Referring to the figure we see that all the output pin outs of the IC are configured to the gates of the corresponding SCRs, and the LED are connected across the positive and the anodes of the scr.

When the IC outputs start generating the shifting pulses, the SCRs close one after the other, illuminating the LEDs in sequence and latch the illuminations in the incrementing order until the last LED is lit. After this the whole array switches OFF.

The switch-off feature of the LED chain is implemented by T3 and is introduced exactly for this function.

T3 being a PNP transistor, remains switched ON as long as the output at pin #11 is low. Pin #11 being the last pin out in the whole sequence remains at logic low until the sequence concludes over it, making it also go high.

As soon as pin #11 becomes high, the base of T3 is inhibited from conduction, switching off the power to the LEDs and the SCR.

The SCR latch breaks, shutting off the whole array and the sequence gets initiated again from LED 1 at pin #3. The shifting or the sequencing of the outputs is directly depended on the frequency of the input clocks, applied at pin #14 of the IC.

Any astable multivibrator may be used for sourcing the clocks. Here we have used the common transistor type of AMV, which is perhaps the most simple to build and configure.

C1 and C2 may be varied for getting different clock pulses that would in turn decide the forming rate of the LED bar. Alternatively you may add VR1 and VR2 in series with R2 and R3 for directly varying the display rates as desired.

The capacitor at the base of T3 is placed so that the transistor switches after a while, and allows the last LED at pin #11 to light up completely before the whole “bar” gets shut off.

Resistors R5 to R15 are included to restrict the current to the SCR and also to stop the IC from getting unnecessarily heated up.

The circuit may be operated right from a supply range of 5 volts to 15 volts DC. If the supply is selected 12 volts, 4 LEDs can be accommodated with a series limiting resistor (not shown in the diagram, but is required).

The post explains how to build an 18 LED chaser circuit through a simple cascading of two 4017 ICs, and some passive electronic components.

What is a Light Chaser Circuit

Decorative lights arranged in different moving patterns look very interesting and are surely eye catching and that’s why these types of lighting arrangement have gained immense popularity in today’s world.

Though the more complex lighting might need the incorporation of microcontroller ICs, simpler yet very interesting light effects can be generated through ordinary ICs, which require very few components for the configuration.

A light chaser circuit is a configuration which generates a running or chasing light pattern which goes on repeating itself from start to finish, producing a very eye catching and fascinating light pattern. The lights connected is mostly LEDs, however it can be modified for using with mains operated lamps also.

How the 18 LED Chaser Works

Here we are discussing how to make a simple 18 LED light chaser circuit which can be built by any newcomer in the field albeit the individual has some knowledge of soldering and regarding the commonly used electronic components.

The circuit of a light chaser discussed here utilizes the popular Johnson’s decade counter IC 4017 for getting the desired light chasing effect. IC 4049 is used as the Oscillator

Another IC 4049 provides the clock signals to the counter ICs. We all have probably seen how the IC 4017 can be configured for creating the light chasing effect using LEDs, however the number of maximum LEDs supported by this IC is not more than ten. In this article we’ll learn how to make an eighteen LED light

chaser by cascading two of these ICs.

Cascading two IC 4017 Johnsons Counter for the 18 LED Effect

Looking at the above 18 LED light chaser circuit figure we see how the two ICs are configured so that the “chasing” of the LEDs at its outputs are carried on for 18 LEDs. The diodes included in the circuit especially are responsible for switching the ICs into a cascading action.

The diodes make sure the IC outputs are carried forward from one IC to another, so that the “chasing” effect is pulled for the entire 18 LEDs in the array.

The whole circuit can be built over a general purpose PCB, and connected together by soldering with the help of the shown diagram.

In this post we learn how to build a homemade LED driver with dimmer and charger circuit for illuminating a 3D moon from a 5V USB source.

The idea was requested by Mr. John Sweden.

LED Driver Circuit with Charger/Dimmer

The Request:

Dear Swag,

I've been a visitor to your website for many years and wonder if I may ask your advice please.

My friend in the US has an almost 2-year-old grandson who loves the moon! I hope it shines in his life as it has in mine. I'm a little older than he is (75) and have recently started to explore 3D printing on an Ultimaker 2+ printer.

I would like to print him a 3D moon-sphere bedside lamp, maybe 12 to 15cm in diameter. It will be hollow and will use a model created by NASA with a hi-res representation of the moon with its craters and surface features.

The white PLA (polylactic acid) filament I'll use is translucent and will allow a small LED to light it from the inside.

The light I was hoping to use is a small-footprint, rechargable battery-powered PCB module made in Malaysia but no longer manufactured. The module slides in through a hole in the bottom of the moon and the whole thing sits on a base.

Do you know of a DIY circuit or module in your library that might be suitable for this project?

I very much appreciate your help Swagatam!

Thank you,

John Sweden

Designing the DC LED Driver

As per the request, for illuminating the 3D moon with a natural feel, we would require a bi-color power LED, 5V LED driver circuit, a current controlled Li-Ion Charger, a touch operated switch and a Li-ion Cell.

I have selected higher specs for all the parameters for the present design, however for lower specs, the materials can be scaled down appropriately as per user preference.

LED Specs:

Bi-Color, Warm White, Cool Blue.

3.3V

0.9 amp current

3 watt, SMD

Battery Specs:

The battery can be a standard Li-ion or Lipo Cell rated at 3.7V, 3000mAh.

The Circuit schematic:

Circuit Description

Referring to the above shown touch operated 3 D moon LED driver with charger dimer circuit, the supply input is obtained from a 5V source such as a USB, which can be assumed to be a constant voltage input.

The TIP122 along with Ry and the associated resistor, preset forms a simple current controlled charger circuit for the attached Li-Ion. The preset is adjusted to fix an approximately 4V across the Li-ion cell terminals.

Ry is appropriately calculated to make sure that the current to the battery never exceeds the 0.5C rate, which may be around 1.5 amps for the proposed 3000mAH battery. This TIP122 must be mounted over a suitable heatsink.

Ry may be calculated a follows:

R = V/I = (5 - 4) / 1.5 = 1/1.5 = 0.66 ohms,

wattage = 1 x 1.5 = 1.5 watts, or 2 watts

The DC to DC UPS Stage:

In the adjoining stage, we can see a few 1N5408 diodes positioned for creating a DC to DC UPS feature, which ensures that the LED inside the 3D moon continues to remain illuminated without an interruption even while the 5V USBsource is removed or during a power failure, with the help of an automatic back up from the Li-ion cell.

Pin#3 which is the start pin of the IC and is supposed to be activated during power switch ON, is connected with one of the LED cathode pins through a TIP122 driver stage and a current limiter resistor Ry.

Let's assume this LED pin to be associated with the warm yellow color section of the LED, and will be responsible for generating a warm yellowish effect on the 3D moon illumination.

The next subsequent pins of the IC 4017, namely pin#2,4,7,10 are all supposed to incorporate identical TIP122 stages with varying Ry values connected and associated with the warm yellow pin of the LED. The pinout details are not shown in the diagram due to lack of space, and since it is identical to the TIP122 stage attached with pin#3 of the IC and just needs to be replicated. The only difference being the value of the Ry which needs to be incremented suitably through calculation.

This implies that when these pins are sequentially toggled will enable a sequential dimming on the 3D moon LED brightness for the warm yellow section off the LED.

In exactly similar fashion pin#1 which initiates next to pin#10 can be seen associated with the other cathode pin of the LED through an identical TIP122 driver stage and a Ry current limiting resistor. The "cool blue LED" is supposed to get illuminated at this pin when the sequential toggling activates this pinout of the IC.

The following subsequent pinouts of the IC are supposed to have identical TIP122 stages for the cool blue LED side, as done in our above explanation with incrementing Ry values, connected with the cool blue pin of the LED.

When sequentially toggled pin#1 will illuminate the 3D moon with a cool blue bright light effect, and the next subsequent pins can be sequentially toggled for dimming this cool blue illumination to the desired lower levels.

As soon as the sequence reaches the last pinout of the IC 4017, which is pin#10, the sequence is designed to flip back to pin#3 and illuminate the warm yellow LED. In this way the 3D moon can be illuminated in two color with a sequential dimming effect.

The LED dimmer Switch.

The two BC557 attached to pin#14 of the IC 4017 are used for creating logic signals for the IC 4017 through finger touches, at the base of the BJT pair. Each touch results in a single sequential shift across the pinouts of the IC from pin#3 to pin#10 and back to pin#3 for the repetition.

Calculating the Dimming Resistor Ry

The Ry current limiter resistor and the dimmer resistor for the yellow and the blue sections of the LEDs may be calculated with the help of the following formula:

Ry = 4 - 3.3 / LED current

Here 4 is the input supply to the LED, 3.3 is the LED standard operating voltage, and the LED current is the amps which is responsible for implementing the dimming effect on the relevant sections of the bi-color LED. Therefore this current value needs to be calculated appropriately for enabling a sequentially decreasing current across the driver stages associated with the relevant pinouts of the IC 4017. Lower current selection will result in higher values resistors generating higher dimming effect on the 3 D moon illumination.

This concludes the making of the proposed 3D moon LED driver circuit with sequential dimming effect, if you have any doubts you may feel free to express them through comments...